Priming bubble..

[splitshot]

Why on some units, but not others?

Seems like the upper end equipment comes without one.Why put that extra fail point in the fuel system?

Dumb question, but one of those I keep scratching my head over.

 

[D'Animal]

They are actually Purge Primers. They simple purge the air out fo the fuel system to make the unit easier to start.

It is tied into the fuel pressure inside the carburetor and the choke mechanism.

The older units without the purge primer generally have a choke plate with no hole in it. They are easy to start but also easy to flood the engine when starting.

The newer units with the purge primer generally have a hole in the choke plate. It is harder to start since you are not getting a true "Choke" so they put the purge primer on them to aid in starting.

Cheap-O units do not generally have them since it is another cost of manufacturing.










I sure hope you are talking about Out Door Power Equipment. LOL